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Zielflug [23.3K]
3 years ago
13

Find S7 for the geometric series 2 + -6 + 18 + -54 +…

Mathematics
1 answer:
nikitadnepr [17]3 years ago
8 0

Answer:

  1094

Step-by-step explanation:

The sum of terms of a geometric series is given by ...

  Sn = a1·(r^n -1)/(r -1)

You want the sum for ...

  a1 = 2, r = -3, n = 7

Filling in the numbers, we get ...

  S7 = 2·((-3)^7 -1)/(-3-1) = 2(-2188)/(-4)

  S7 = 1094

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I need help with this (don't answer if you don't know)
SashulF [63]

Answer:

Step-by-step explanation:

Here's a step by step tutorial on your calculator on how to do this.  

Hit "stat" then "1: Edit".  If there are numbers there, arrow up to highlight L1, or L2, or wherever there are numbers.  Hit "clear" then "enter" and the numbers will be gone.  In L1, enter the Practice throws values.  Press 3 then enter, then 12 then enter, then 6 then enter, etc. til all of them are in L1's column.  Then arrow over to L2 and do the same with entering all the Free Throw values.

When you're done, hit "stat" again, then arrow over once to "calc" and #4 should say LinReg.  That's a linear regression equation.  If you have a TI 83, just hit enter and you'll get the equation in the form y = mx + b.  If you have a TI 84 or 84+, you'll need to arrow down to the word "calculate" and then you'll see the equation.

One thing...if you have not turned your diagnostics on, you wont be able to see the coefficient of determination (the r-squared value).  To make sure it's on:

Hit 2nd, then 0.  You have opened up the catalog which lists every single thing your calculator can do in alphabetical order.  The hit the button UNDER the MATH button (x to the negative 1) and scroll down until you see "diagnosticsON" and hit enter twice.

If you need to recall the linear regression equation, hit "stat", then "calc" then either enter or calculate and you'll get the linear equation again and an r value and an r-squared value.  The closer that number is to 1, the better the data fits that model.  I got that the equation is

y = 2.352x - .852 with an r-squared value of .844

To get the quadratic regression equation, hit "stat" then "calc" then choose #5, QuadReg.  Repeat the process to calculate your equation.  Mine was

y=.073x^2+1.205x+2.555; r^2=.855

And for the exponential regression, choose ExpReg (mine is under 0.  Yours may be some other number.  Just arrow down til you find it, it's there!) My ExpReg equation was

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It appears that the r-squared value is the highest in the quadratic regression equation, so that's the best fit.

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3 years ago
Equivalent ratios for 5:13
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10:26
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20:52
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6 0
4 years ago
Read 2 more answers
HELP............Graph. y+1=1/3(x−3) (it has to have 2 points)
natta225 [31]
The intercept method of graphing is quick and easy.

Find the x-intercept by setting y = 0 and solving for x:

y+1=1/3(x−3)   =>   0<span>+1=1/3(x−3)
  Multiply both sides by 3:  3 = x - 3.  Then x = 6, and the x-int. is (6, 0).

Find the y-int by setting x = 0 and solving for y:

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Mult both sides by 3:  3y+3 = -3, so that 3y = -6, and y = -2.
Then the y-intercept is (0,-2).

Plot these 2 points.  Then draw a line thru them.</span>
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adam is three years younger than twice bobs age. in 5 years adams age will be 8 years more than bobs age. what are their 2 ages
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Adam is 9 years old and Bob is 6. Twice Bob’s age is 12, three years younger than that is 9. If Adam is 9 now then in five years, Adam will be 14, which is 8 more than 6.
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NEED HELP ASAP!!!!!!!!!!!!!!!!!!!!!!!!!
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Step-by-step explanation:

how can I help you ........

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